Investigating heavy metal resistance, bioaccumulation and metabolic profile of a metallophile microbial consortium native to an abandoned mine Anna Rosa Sprocati ⁎ , Chiara Alisi, Lia Segre, Flavia Tasso, Mara Galletti, Carlo Cremisini ENEA, via Anguillarese 301, 00060 Rome, Italy Received 7 October 2005; received in revised form 17 January 2006; accepted 24 January 2006 Available online 23 March 2006 Abstract Contaminated sites represent new ecological niches where historical pollution has originated an unusual microbial biodiversity. The knowledge of these microorganisms contributes to the discovery of new pathways and metabolic networks and may offer potential solutions for damaged areas. In the present work seven microbial consortia have been isolated from an abandoned mine of blend and galena (Ingurtosu, Italy) through a selection for resistance to zinc (tested up to 40 mM in solution). All the consortia were able to accumulate zinc and the best accumulator, named Ing5, has been studied for the following characteristics: resistance and accumulation of Zn, Cd, Hg, bioaccumulation mechanisms of Zn, and influence of Zn and Cd on the metabolic profile. The results indicate that the consortium Ing5 bears resistance systems for Cd and Hg as well as Zn and that, for some of the 5 isolates belonging to Ing5, the resistance thresholds are higher in consortium than in pure culture. The prevalent mechanism for zinc accumulation can be reasonably considered to be metabolism-dependent, inducible and regulated by metal concentrations. The study on the metabolic profile, carried out by the Biolog system, shows that Zn exerts a very low influence on the metabolic profile and that this influence can also be positive; Cd has a stronger negative influence but that, despite this, the consortium is able to maintain a wide metabolic potential in the presence of heavy metals. These features of Ing5 make it a good candidate for biotechnological applications and for further investigation of the degradation of organic pollutants in the presence of metals. © 2006 Elsevier B.V. All rights reserved. Keywords: Zinc; Cadmium; Biolog; Bioremediation 1. Introduction The practical difficulties of sampling and the com- plexity to detect and grow microorganisms make it questionable whether the inventorying of the world's microbial diversity is practicable, but the importance of microbial function demands that our knowledge is extended (Convention on Biological Diversity, 2002). Microbiological explorations of new ecological niches can widen the knowledge of the microbial domain and help in finding a response to different research needs in several fields. Contaminated sites represent ecological niches where historical pollution has resulted in an unusual microbial biodiversity, exerting environmental pressure on fundamental ecological parameters such as abundance, diversity, nutrient recycling, and food Science of the Total Environment 366 (2006) 649 – 658 www.elsevier.com/locate/scitotenv ⁎ Corresponding author. ENEA-Casaccia, via Anguillarese 301, 00060 Rome, Italy. Tel.: +39 0630484495; fax: +39 0630484808. E-mail address: sprocati@casaccia.enea.it (A.R. Sprocati). 0048-9697/$ - see front matter © 2006 Elsevier B.V. All rights reserved. doi:10.1016/j.scitotenv.2006.01.025